Turntables are also called phonographs or record players. Turntables may be characterized into different types. Three most common types of conventional turntables include direct drive type turntable, idler drive type turntable and belt drive type turntable. In examples of the present disclosure, applicant's test results show that the present disclosure significantly improves sound quality of the direct drive type turntable; improves sound quality of the idler drive type turntable; and somewhat improves sound quality of the belt drive type turntable.
A direct drive type turntable usually has the greatest amount of instantaneous torque available to the platter (for very good transient response and low bass reproduction). However, one downside is that an increased motor noise level is coupled into the music. Some direct drive type turntable manufacturers use a very heavy body (also called a base or plinth) in an effort to reduce motor vibrations.
An idler drive type turntable is very similar to a rim drive type turntable. The idler drive type turntable uses elastomeric wheels to couple the motor to the platter. The idler drive type turntable uses elastomeric motor mount (for example, rubber). One downside is that it couples more motor noise into the music.
The belt drive type turntable uses an elastomeric belt that couples its driving motor to its platter while filtering out the motor's vibrations. This belt has a tendency to oscillate and to stretch slightly during loud musical passages which dulls the musical peaks. One solution of the belt drive type turntable is to use a heavy platter which acts as a flywheel. Low mass belt drive turntables suffer from speed instabilities due to needle drag during loud musical passages so as to dull musical transients. The belt drive type turntable usually mounts the motor on an elastic material or a viscoelastic material such as rubber. The elastic material has similar problem as the drive belt. Some belt drive turntable manufacturers mount the motor in an enclosure that is separated from the turntable body to reduce vibration and to take advantage of a stiffer mounting system. This type of solution requires a sturdy and rigid surface for them to rest on.
A conventional magnetic coupled platter turntable is expensive. It uses magnets to couple energy from one platter to another. It requires strong supporting pillars attached to arm boards to keep the platters from sticking to one another. The strong supporting pillars drain energies from the tonearm energy loop and degrade sound qualities.
U.S. Pat. No. 3,082,635 to Grado, U.S. Pat. No. 8,406,112 to Merrill et. al., and U.S. Pat. No. 8,611,201 to Desjardins describe unwanted energies of turntables affecting sound qualities. The energy of a motor of a conventional turntable propagates through at least part of a platter of the conventional turntable. The propagated energy causes vibration to be superimposed onto a record that is played by the conventional turntable. Vibrations induced by the motor of the conventional turntable propagate through a base of the conventional turntable. The propagated, motor induced vibrations introduce uncertainties to a relative location between a needle of the turntable and the record. It adds noise and distortion to a desired musical signal that the needle supposed to pick up. A quality conventional turntable reduces vibrations by introducing a heavy platter and a heavy base. However, a large mass of the heavy platter and a large mass of the heavy base store and release vibrational energies (analogous to an echo effect). The echo effect results in a heavy or dead sound signal.
A conventional turntable has the arm board mounted on a same plate that provides support for the platter. Therefore, the tonearm energy loop will be affected by the motor's energy loop through the motor's mounting system as well as through the platter itself. The tonearm energy loop includes a stylus, a tonearm assembly, an arm board, a bearing assembly, a shaft, a platter, a platter mat (if used) and a vinyl record.
One way to reduce a degradation of the musical signal or the sound signal is not to mount the record on the platter of the conventional turntable. Instead, the present disclosure, adds a platter supported and driven turntable between the record and the platter of the conventional turntable. The platter supported and driven turntable is structurally supported by the platter of the conventional turntable. The platter supported and driven turntable is driven by a rotation energy from the platter of the conventional turntable.
A mat of the platter of the conventional turntable may provide a vibration dampening effect to achieve a pre-determined level of vibration isolation. The mat at a point of contact may act as a constrained layer dampening system.
In examples of the present disclosure, the rotational energy from the platter of the conventional turntable is transferred to a lower platter of the present disclosure through a spacer ring. The spacer ring may be disposed between the platter of the conventional turntable and the lower platter of the present disclosure. The spacer ring may be proximate to an outer portion of the platter of the conventional turntable. The rotational energy is then transferred to a shaft of a spindle of the present disclosure. An arm board (also called a tonearm board) and flanged sleeve bearing are attached to the shaft.
To use the platter supported and driven turntable of the present disclosure, a user sets the platter supported and driven turntable of the present disclosure atop the platter of the conventional turntable. The user may attach a new tonearm assembly or a tonearm assembly of the conventional turntable to one end of the arm board of the present disclosure. In one example, the other end of the arm board of the present disclosure may be affixed to a ballast (a heavy and non-vibration prone object). In another example, the other end of the arm board of the present disclosure may be affixed to the conventional turntable.
It is advantageous to place the platter supported and driven turntable of the present disclosure and the conventional turntable on a rigid surface so as to couple the two together. One advantage of the setup of the present disclosure is that records can be played with greater clarity. The propagation of vibration energy of the motor through a tonearm energy loop including a stylus, a tonearm assembly, an arm board, a bearing assembly, a shaft, a platter, a platter mat (if used) and a vinyl record is greatly suppressed. The present disclosure uses a very low mass tonearm energy loop.
In one example, the platter supported and driven turntable of the present disclosure retrofits to a conventional turntable. In another example, the platter supported and driven turntable of the present disclosure may be mounted on or built into a newly-built turntable.
It is advantage to facilitate a low mass tonearm energy loop that is not connected to the supporting elements of the turntable. This enables musical transients to rise and fall effortlessly. And it offers greater rejection of airborne vibrations.
A cantilever design enables the ballast to provide substantially more inertia against rotational energy compared to a conventional turntable because the ballast is further away from the axis of rotation of the spindle. A single ground path avoids ground loop effects. The lower circular platter may have a damping material affixed to it. In one example, the lower circular platter may couple with the platter of a conventional turntable through spikes, small disks, or small balls. In another example, the lower circular platter may directly contact with the platter of the conventional turntable. In one example, the spacer ring is a continuous ring. In another example, the spacer ring comprises a plurality of segments.
In examples of the present disclosure, the lower circular platter may directly contact with the platter of the conventional turntable. The lower circular platter, the mat of the platter of the conventional turntable and the platter of the conventional turntable may form a constrained layer dampening system (which dissipates vibrations as heat). This constrained layer dampening system is easily tunable by using different mat materials with different thickness. The constrained layer dampening system in this application may also function somewhat like a bullet proof vest or a bullet proof glass. The energy is dissipated across the material instead of through it.
An outer profile of the arm board may have different shapes including a boomerang shape and a letter “S” shape.
In examples of the present disclosure, the conventional turntable may provide three or more points of support to the platter supported and driven turntable of the present disclosure. In examples of the present disclosure, three or more rigid and dampened feet may be used to support the arm board. It allows an option of enclosing the existing turntable for cosmetic purposes. Not all conventional models of turntables will be suitable for use with the present disclosure. Some conventional models do not have enough power to drive the platter supported and driven turntable of the present disclosure steadily or up to a proper speed. Some conventional models do not provide stable support to the platter supported and driven turntable of the present disclosure.